Revert "cpupools: update domU's node-affinity on the cpupool_unassign_cpu() path"

Revert "cpupools: update domU's node-affinity on the cpupool_unassign_cpu() path"

This reverts commit 93be8285a79c6cbbf66c8681fec1d1bfb71d84cc.

At the point this patch calls domain_update_node_affinity(), the vcpu
hard affinities have not yet been updated; so calling it at this point
can in some circumstances trigger an ASSERT().

domain_update_node_affinity() is already called in
cpu_disable_scheduler(), so adding it to cpupool_unassign_cpu() is
redundant.  Simply reverting the patch is sufficient.

Acked-by: George Dunlap <george.dunlap@eu.citrix.com>